The use of lightweight materials including aluminum body panels is increasing due to the need to meet stringent fuel economy goals. Light materials include aluminum, composite fiber reinforced parts, magnesium parts, and the like. These types of materials present challenges due to reduced ductility and formability. In addition, aluminum panels, reinforcements and brackets have reduced tensile strength and are more difficult to weld.
Tailgates for pick-up trucks are generally constructed with an outer panel and an inner panel that are assembled together and both have class-A surfaces that are visible on the vehicle. One problem with manufacturing tailgates includes the need to form surfaces of the panels without splits or wrinkles in the corners of the inner panel. Another problem is that the inner and outer panels must be adequately reinforced to avoid “oil canning,” a condition where the panel deflects when pressure is applied to the inner or outer panels. Another problem is the need to provide durable mounting locations for connecting hinges and latches.
This disclosure is directed to addressing the above problems and other problems as summarized below.